Building panels

ABSTRACT

Structural composite panels constructed by mechanically joining two sheets of material preferably plywood by two or more thin web sections preferably sheet metal truss stampings. The web sections have integral edge preparation in the form of barbs or prongs which penetrate into the sheet materials by normal pressure at assembly, the sheet materials then functioning as flanges in the composite beam panel. The web may be solid except for edge preparation or blanked from sheets or strips in a truss form permitting the most efficient use of web material in the structural composite panel. The blank design layout procedure also provides forming of web material to produce needed column strength and resistance to buckling in web elements. Prongs generate attachment by friction, and by mechanical locking of prongs into flange materials obtained by deformation of prongs during insertion.

"United States Patent [19 Cargill et al.

14 1 Sept. 16, 1975 BUILDING PANELS.

22 Filed: Feb. 9, 1973 21 Appl.No.: 331,193

Related U.S. Application Data [6 3] Continuation-impart of Ser. No. 229,786, Feb. 28,

1972, abandoned.

[52] U.S. Cl. 52/615; 52/650; 52/694;

85/1 1; 85/13 [51] Int. Cl. E04b 2/32 [58] Field of Search 52/650, 694, 696, 630,

52/620, 659, 615, 693, 618, DIG. 6, 690; 85/l1,13, 14, 31

Law 52/694 X 3,292,481 12/1966 Couch 85 13 3,382,752 5/1968 Black et al.. 85/13 3,538,668 11/1970 Anderson.... 52/615 3,552,086 1 1971 Allen 52/618 Primary Examiner-Emest R. Purser Assistant Examiner-Carl D. Friedman Attorney, Agent, or Firm Farley, Forster and Farley [5 7] ABSTRACT Structural composite panels constructed by mechanically joining two sheets of material preferably plywood by two or more thin web sections preferably sheet metal truss stampings. The web sections have integral edge preparation in the form of barbs or prongs which penetrate into the sheet materials by normal pressure at assembly, the sheet materials then functioning as flanges in the composite beam panel. The web may be solid except for edge preparation or blanked from sheets or strips in a truss form permitting the most efficient use of web material in the structural composite panel. The blank design layout procedure also provides forming of web material to produce needed column strength and resistance to buckling in web elements. Prongs generate attachment by friction, and by mechanical locking of prongs into flange materials obtained by deformation of prongs during insertion.

10 Claims, 27 Drawing Figures SHEET 0F PATENTEUSEP 1 61975 905. 1 Y 1 FIG.I9

F'IG.23

PATENTED SEF I 8 I975 SHEET 7 BF 7 BUILDING PANELS RELATED APPLICATIONS This application is a continuation-in-part of application Ser. No. 229,786, filed Feb. 28, 1972, to become abandoned upon the filing of the present application.

BACKGROUND OF THE DISCLOSURE SUMMARY OF THE INVENTION Applicants invention, in the preferred embodiment, comprises a structural composite steel and spaced plywood panel construction exceedingly simple to manufacture with minimum weight and maximum conservation of material. The fastening prongsare integral with a truss form sheet metal stamping and automatically penetrate, deform and tightly lock the plywood top and bottom sheets from normal lateral pressure in the assembly process which is ideal for automatic high-speed production with relatively unskilled help. Preferably, the stamped steel truss sections are formed from the lowest-cost, hot rolled, sheet steel available and the complementary configuration of each truss allows them to be progressively formed from the solid sheet with virtually no wastage. Portions of the truss between the apices are formed to provide a U-section to increase column strength.

Although ideally adapted to plywood, the invention .is useful with hard board, gypsum board, particle board or any other board material capable of penetration by prongs of the steel truss material. Prior to assembly of the panel, the boards may be faced with vinyl or other finished coating to provide finished side walls, partitions, floors or roofs. In relatively small size, the panels may be suitable as hollow doors. I

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective of a portion of a composite building panel according to the invention;

FIG. 2 is a portion ofa typical truss prior to assembly with plywood sheets;

FIG. 3 is a section along the line 3-3 of FIG. 2;

FIG. 4 is a partial cutaway showing the fastening means at an'apex inserted in relatively thick plywood sheet material;

FIG. 5 shows a partial section of the fastening means at an apex inserted in a material on the same order of thickness as the length of the fastening means;

FIG. 6 is a side view of an alternate truss formed from narrow strip stock; h

FIG. 7' is a partial topview ofthe truss of FIG. 6;

FIG. 8 is an end view taken in the direction in FIG. 6:

FIG. 9 is a top view of the strip after stamping and prior to forming;

FIG. 10 is a side view of an alternate form of prong;

FIG. 11 is an edge cross sectional view of the prongs of FIG. 10 subsequent to insertion;

FIG. 12 is an alternate prong including a barb;

FIG. 13 is an edge cross sectional view of the barbed prong of FIG. .12;

FIG. 14 is aside view of optional prongs with bent tips; v

FIG. 15 is an edge view of the bent tip prongs of FIG. 14;

FIG. 16 is a side view of an optional form of bent tip prongs including stiffeners;

FIG. 17 is anedge view of the bent tip prongs of FIG.

FIG. 18 is an optional undulating web shown in perspective;

FIG. 19 is a fragmentary side view of another alternate truss stamping formed with progressive sectional curvature;

FIG. 20 is a sectional view taken along the line 20-20 of FIG. 19;

FIG. 21 is a section taken along the line 2l2l of FIG. 19;

FIG. 22 is a schematic view illustrating the use of truss elements in a criss-cross configuration;

FIG. 23 is a top elevation of an alternate truss similar to that shown in FIGS. l-5 but having offset prongs at the respective top and bottom apices; and

FIG. 24 is a side view of an alternate solid sheet steel web construction formed with uniform prong spacing.

FIG. 25 is a cutaway side view of an alternate panel truss having a rod tensile member welded to the lower apices;

FIG. 26 is a cutaway end view of the truss in FIG. 25; and

FIG. 27 is a cutaway planview of the truss of FIG. 25.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 top and bottom sheets 10 and 12 made of any suitable material, preferably plywood, are joined together by sheet metal stamped trusses generally denoted by 14. Asshown in FIG. 1, two trusses l6 and 18 are located parallel to each other and perpendicular to the plywood sheets 10 and 12. Typically, a panel 12 feet long in the direction shown by arrow 20 and 4 feet wide in the direction shown by arrow 22 will require five parallel trusses in the case of standard floor panels. Of course, the load bearing requirements of such a building panel for use as a floor, roof or wall structure will determine the spacing of trusses and thickness of the plywood sheets 10 and 12. Thus, a wide variety of load capacity can be accommodated merely by changing the thicknesses of plywood used for the panels and the spacing of truss elements utilized in assembly. This greatly reduces the need for providing different gauges of sheetmetal and'a variety of sizes which would require multiple tooling. Typically, a 6 inches panel spacing is adequate for floor and roof structures and 4 inches spacing for wall panels.

As is evident from FIG. 1, there is ample room for the passage of electric and fluid utilities through the panels and the panels may be manufactured with any form of surface finish desired bottom and top to provide a finished ceiling and floor or inside and outside wall constructions. However, use of the most economical rough structural grade plywood will result in extremely economical panels ready for final treatment either before on site erection or after. The end block 24 for use in attachment to support structures also serves to provide lateral stability to the panel construction. The thickness of the block 24 denoted by 26 may be as desired for the support of any load bearing structure thereabove, whether used as a floor panel or as a wall panel. Typically, the block would be on the order of 2 to 4 inches thickness.

In FIG. 2 a portion of a typical truss 14 is shown prior to assembly with the plywood sheets 10 and 12 above. The truss may be suitably formed from 18-gauge hot rolled 1020 steel or other suitable material. The truss includes apex portions 28 and strut portions 30 with flanges 32 substantially perpendicular to the remainder of the strut 30 as shown in FIG. 3. Prior to bending, the flanges 32 are shown in phantom in FIG. 2. The prongs 34 are integrally formed as shown extending from each apex 28. Each prong 23 is generally tapered and includes a curved portion 36 intersecting a straight portion 38 to create a relatively sharp point. Preferably, the prongs 34 are formed in pairs and as shown in FIGS. 4 and the prongs upon forceful insertion into the plywood 40 or 42 deform in the plane of the sheet metal due to the unbalanced lead design. The original prong shape is shown in phantom in FIGS. 4 and 5 as denoted by 34, and the final shape denoted by 44. Thus, the pairs of prongs are forced to grip tightly and lock the portions 46 of the plywood 40 or 42. Where the thickness of the plywood may be substantially equal to or less than the prong length after penetrating deformation as shown in FIG. 5, a steel backup plate may be applied against the surface 48 during assembly to further clinch the prongs 34.

Returning to FIG. 2, each apex 28 includes a small amount of scrap 50 forming the complementary residue from the matching next adjacent truss separated during the stamping process. As is readily apparent, the edges 52 and 54 of the flanges 32 are complementary to each other thereby eliminating any wastage along the struts 30. The prongs 34 may be the same length at all apices for insertion in plywood and 12 of substantially the same thickness. However, if sheets 10 and 12 of substantially different thickness are to be utilized and the penetration as shown in FIG. 5 eliminated then the prongs 34 for insertion into sheet 12 may be of a different length from those for insertion into sheet 10.

Such different prong lengths are readily accommodated with only the wastage indicated by 50.

Assembly of a typical panel merely requires placing the plywood sheets and steel trusses into position in a press and applying a load sufficient to accomplish complete penetration by the prongs into the plywood. The pre-assemblies may be stacked for simultaneous multiple compression in a stack or adapted for simple automatic single panel assembly. Thus, the configuration is readily adapted to automatic assembly with no hand work whatsoever required. In either case fixturing to maintain the truss members in vertical position during assembly will be apparent to those skilled in the art.

In FIG. 6 an alternate form of truss is shown including prongs 134 of substantially the same shape which extend in parallel rows from each apex 128 as shown in FIG. 8. The struts 130 include flanges 132 folded therefrom, as shown in FIGS. 6 and 7. In this embodimerit, the apexes 128 are wrapped on a mandrel substantially perpendicular to the struts along fold lines 129, best shown in FIGS. 7 and 9. During the wrapping operation, the pre-stamped prongs 134 emerge out of the apexes 128 leaving holes 135, as shown in FIG. 7. The configuration lends itself to a twostep forming process in which FIG. 9 shows a narrow strip stamped with prongs 134 and folded along the struts 130 to provide the flanges 132. In the subsequent step, the strip is wrapped about a rotating mandrel at the angle which the struts made with the plates in the final assembly. This alternate embodiment eliminates all waste metal and lends itself to highspeed roll forming for the continuous production of the truss which may be cut to any suitable length. The separated parallel rows of prongs 134 also contribute to the lateral stability of the composite panel structure.

The assembled panels comprise a stressed skin" type of load bearing structure. When used as a floor or roof panel, the lower sheet 12 may optionally be substantially thinner than the upper plate 10 since it will be loaded in tension through the lower truss connections whereas the upper sheet 10 will be loaded in compression and therefore must resist buckling compression forces as well as localized concentrated loads. In most floor and roof applications the panels will be supported only at their ends, which may correspond to two side walls of a room in a typical floor case, so that the panel becomes loaded as an end supported beam in normal use. The stamped steel truss members are most efficiently used in parallel straight configurations with compressive column loading of intermediate strut elements placing the lower plywood sheet under tension and the upper under compression in only one major longitudinal direction parallel to the truss members. The firm embodiment of the integral prongs assures the transmission of compressive column loading to effectively stress the plywood skin sheets making the composite panel operate effectively as an integral beam structure having webs formed between the spaced plywood sheets. The elimination of separate fastening means for the truss elements and the integral flanges 32 on the struts 30 minimize the material requirements for the structure with the result that the combination and configuration provides a synergistic reduction in actual material requirements for a given load bearing capacity. Productivity is enhanced by the simplicity of assembly and limited number of different size requirements.

FIGS. 10 through 17 disclose several optional prong configurations, each developed to deform into a particular engaging configuration upon penetration of the plywood. The prongs 234 in FIG. 10 are bevelled at 236 and bent in a manner similar to that shown in FIG. 15 so that upon penetration the prongs 234 will be deformed both toward each other in matching pairs, as above, but with an additional twist. The result will be deformation substantially as that shown in FIG. 11. Thus, the prongs 234 are bent toward each other in the plane of FIG. 10, and simultaneously twisted away from each other in the perpendicular view shown in FIG. 11. Such a severe deformation will tightly lock the prongs into the plywood 240.

In FIG. 12 the prong 334 includes a barb 336. Upon penetration of the prong 334 into the plywood 340, as shown in FIG. 13, the barb 336 willengage the'plywood in a manner as shown to prevent extraction of the prong from the plywood. In manufacturing the prong 334, the barb"336is-'cut-and bent outwardly from the prong334 and thereforc is resiliently loaded .when the prong is forcefully inserted into the plywood; The resilient loading forces the .prong'outward, as shown in FIG. 13. Extraction forces tend to lock the prong 336 tighter in the plywood 340.

In FIGS. 14 and 15, the prongs 434.are symmetrical inthe planeof FIG. 14. As shown in,;F.lG. 1-5,the tips 436 areoppositely directed. The result upon penetration is a deformation substantiallyas thatshown in FIG. 11. However, the twist developed-by the prongs of FIG. will not occur with the prongs of FIG. 14..Nevertheless a substantially resistance to extraction will be developed, by frictionand the oppositely directed deformation shown in FIG. 11. j

In FIGS 16 and-l7 ,the tips 536 ofthe prong s 534 are bent ,tofthe same side of the apex 528 The prongs 534 include a beveled portion 538 which in combination with the bent tips 536 cause a twisting deformation in a manner similar; to FIG. 10.,I-Iowever, the twists will be directed generally toward the same side of the apex 538 in a manner that tends to further separate each pair since the bevels are on the nearside: of each pair. The prongs 534 include stiffening dimpleis 5 3'2 to reduce the deformation adjacent the" apex 528. The prongsQof FIGS. 16 and 17 aredirected to insertion in relatively thick plywood, where it is desired that the prongs extend deeply into the plywood with the twisted and curled tips 536 deeply embedded. Without the stiffeners'532, the prongs 534 would tend'to curl sooner upon insertion and therefore not penetrate the plywood as deeply.

In FIG. 18, an undulating or corrugated web is shown as an option to replace the zig-zag configuration. The undulating form includes prongs 634 extending from the undulating web 630 on opposite edges every half wave length. As shown by the cutout notches and tabs 650 therebetween, the undulating configuration is also complementary in a manner that substantially eliminates waste material. Although adaptable to any size panel, the undulating configuration of FIG. 18 is ideally suited for relatively small panel structures, such as ho!- low doors, thin non-lead bearing movable wall partitions and curtain wall panels.

As shown in FIGS. 19 through 21, the strut generally denoted by 730 may be formed to a semi circular cross section best shown in FIG. 20, midway between the apices 728 shown in FIG. 19. Since the apices 728 are substantially flat, a gradual progressive curve form is generated, as further illustrated in FIG. 21.

FIG. 22 schematically indicates the placing of the trusses generally denoted by 714 in planes perpendicular to and intersecting each other in the panel. Such transverse perpendicular trusses will provide lateral rigidity in a similar manner to the block 24 in FIG. 1. It is also clear that such a transverse truss also performs a function similar to bridging in conventional wooden floor joist construction. With the zigzag trusses shown, a large number of transverse trusses may be incorporated to provide a rigid stressed skin structure suitable for support from all four side extremities of the panel.

As a further option, FIG. 23 shows the truss generally denoted by 814 with the apices 828 connected by struts 830 offset to provide lateral stability in a manner similar to the rolled form of the truss shown in FIGS. 6 through 9. Such trusses may be assembled in the panel in parallel asymmetric orientation.

In FIG. 24 the solid sheet steel web is formed in straight strips with uniformspacing of simple'tapered prongs 934extending between adjacent recesses 935 from which'the projecting prongs of adjacent web elements are formed. Diagonalstiffeningindnt'ations 936 provide compressive-strength analogous to truss elements 1 r An alternate form ofpanel isconstructed as shown in FIGS. 2 5-27 whereinasingle upper plywood sheet 1010 is engaged by trusses 1 014 with the upper apices 1028 .alternatingly engaging the upper sheet 1010 -in staggered or oppositelyoffset relation to the lower apices 1028' extending along the 'centerplane of each truss. The prongs 1034 on the upper. apices l028.engage thesheet 1010 as in the other species disclosed herein; however, the prongs-1034' on the lower-apices 1028 'are welded or otherwise suitably. fastened to a rod preferably square which comprises the lowertensile chord 1012 of the truss 1014. As shown in FIG. 27 the upper apices 1028 lie in'planes spaced on either side and parallel to the single plane of the lower chord 1012 with the struts 1030 extending diagonally downwardto the lower apices 1028". Thus the offset upper connecting points of each truss 1014 anchored in-= the sheet plywood providelateral stability without interconnection or bridging between adjacent parallel trusses in the lower plane of the chords 1012. Since the loading of the lower chord is normally restricted to tensile forces in the longitudinal direction, a steel rod, which may be in the order of 5/16 inch square, welded to the lower apices 1028 or prongs 1034' thereon, provides adequate strength with an opening ceiling between the chords which may be desirable as for site installation of duct work, plumbing, electrical conduits and the like.

In preferred prong configurations described above and illustrated in the drawings, the prongs have been disclosed in symmetrical pairs with each individual prong asymmetrical to provide desired bending in the longitudinal plane of the sheet metal upon penetration into the plywood. This is an important feature of the present invention for several reasons: The bending forces arising from the asymmetrical form of the prong may be controlled with precision since they arise from die sheared edges which produce exact dimensional forms with high repetitive accuracy; bending in the major plane of the cross section results in a very high gripping force against pullout and the configuration of the plywood between the prongs as illustrated in FIG. 4, for example, may be accurately controlled for maximum pullout and sheer strength. It is desirable that each prong be provided with a tapered base so as to develop a progressive preload compression on the adjacent wood fibres as the prong is progressively pressed into assembled position thereby providing a high resistance to initial deflection from loads which place the prongs under sheer load relative to the plywood in the longitudinal plane of the truss.

Where the web elements between plywood sheets are continuous as in the case of FIGS. 18 and 23, greater sheer strength may be realized through the uniform spacing of prongs throughout the length of the panel. A simple tapered prong form such as illustrated in FIG. 24 may suffice if the panel usage does not subject the opposed plywood sheets to large separating forces.

We claim:

l. A structural composite panel comprising a penetrable panel sheet, a plurality of intermediate sheet metal web means, apices of said web means including integral fastening prongs penetrating the panel face, and chordal tensile means engaging other apices of said web means spaced from said panel face, each of said web means comprising a sheet metal stamping having a series of longitudinally spaced apices extending along one edge extremity, a complementary series of intermediate longitudinally spaced apices extending along an opposite edge extremity, angularly extending flanged strut portions joining alternate apices of opposite edges to form an integral continuous zig-zag web means said truss means having an edge adapted attached to said penetrable panel sheet extending normal to said web means characterized by integrally formed pairs of asymmetrical prongs extending substantially in the plane of said sheet metal producing opposite bending movement toward each other in the plane of said prong in penetrating said adjoining element, the bases of each pair of prongs being substantially spaced with an intermediate straight edge portion engaging the adjacent surface of and limiting prong penetration into said adjoining elment and locking each pair of prongs of said web means to a substantial mass of said adjoining element, said web means having a complementary configuration adapted for progressive multiple truss stampings from a single metal sheet substantially free of intermediate scrap blanking material.

2. The component of claim 1 wherein each of said prongs includes a curved beveled edge to produce said bending movement during penetration.

3. The composite panel of claim 1, said tensile element comprising a common sccond pcnetrable panel sheet engaging said plurality of web means, said other edge also having integrally formed panel sheet pcnetrating prongs.

4. The composite panel of claim 1, components, and means for stabilizing said rods against lateral displacement, comprising alternate strut engagement with said panel sheet in parallel planes spaced on either side of the plane of said metal rod.

5. The composite panel of claim 1, said panel sheet comprising plywood.

6. The composite panel of claim 1, said tensile element comprising a common second penetrable panel sheet engaging said plurality of web means, said other edge also having integrally formed panel sheet penetrating prongs, said panel sheets both comprising plywood.

7. The panel of claim 1 wherein the panel sheet is plywood, and the chordal tensile means comprise metal rods secured to said other apices.

8. The panel of claim 7 wherein apices adjacent the panel sheet are alternatingly spaced from a plane defined by a chord and perpendicular to the panel sheet.

9. The panel of claim 1 wherein the panel sheet and chordal tensile means both comprise plywood engaged by similar integral fastening prongs.

10. The panel of claim 1 wherein at least some of the web means intersect to provide cross stability to the panel.

September 16, 1975 Don A. Cargill, Paul M. Corp, Lloyd M. Fo ster PATENT NO.

DATED iNVENTOiKS) 1 2; the above-ideniir'ied patent and that said Letters Patent 3: appea s Col. 5, line 43, "non-lead" changed to read non-load Col. 7, line 15 (claim 1) "truss" changed to read web Col. 7, line 24 (claim 1) "elment" changed to read element- Signed and Sealed this thirtieth Day of March 1976 [SEAL] A ltes t:

RUTH C. MASON Allesling Officer 

1. A structural composite panel comprising a penetrable panel sheet, a plurality of intermediate sheet metal web means, apices of said web means including integral fastening prongs penetrating the panel face, and chordal tensile means engaging other apices of said web means spaced from said panel face, each of said web means comprising a sheet metal stamping having a series of longitudinally spaced apices extending along one edge extremity, a complementary series of intermediate longitudinally spaced apices extending along on opposite edge extremity, angularly extending flanged strut portions joining alternate apices of opposite edges to form an integral continuous zig-zag web means said truss means having an edge adapted attached to said penetrable panel sheet extending normal to said web means characterized by integrally formed pairs of asymmetrical prongs extending substantially in the plane of said sheet metal producing opposite bending movement toward each other in the plane of said prong in penetrating said adjoining element, the bases of each pair of prongs being substantially spaced with an intermediate straight edge portion engaging the adjacent surface of and limiting prong penetration into said adjoining elment and locking each pair of prongs of said web means to a substantial mass of said adjoining element, said web means having a complementary configuration adapted for progressive multiple truss stampings from a single metal sheet substantially free of intermediate scrap blanking material.
 2. The component of claim 1 wherein each of said prongs includes a curved beveled edge to produce said bending movement during penetration.
 3. The composite panel of claim 1, said tensile element comprising a common second penetrable panel sheet engaging said plurality of web means, said other edge also having integrally formed panel sheet penetrating prongs.
 4. The composite panel of claim 1, components, and means for stabilizing said rods against lateral displacement, comprising alternate strut engagement with sAid panel sheet in parallel planes spaced on either side of the plane of said metal rod.
 5. The composite panel of claim 1, said panel sheet comprising plywood.
 6. The composite panel of claim 1, said tensile element comprising a common second penetrable panel sheet engaging said plurality of web means, said other edge also having integrally formed panel sheet penetrating prongs, said panel sheets both comprising plywood.
 7. The panel of claim 1 wherein the panel sheet is plywood, and the chordal tensile means comprise metal rods secured to said other apices.
 8. The panel of claim 7 wherein apices adjacent the panel sheet are alternatingly spaced from a plane defined by a chord and perpendicular to the panel sheet.
 9. The panel of claim 1 wherein the panel sheet and chordal tensile means both comprise plywood engaged by similar integral fastening prongs.
 10. The panel of claim 1 wherein at least some of the web means intersect to provide cross stability to the panel. 